Electrostatic dust precipitator



Dec. 25, 1951 I. R. CUMMINGS 2,579,552

ELECTROSTATIC DUST 'PRECIPITATOR Filed Jan. 15, 1947 2 SI-IEETS-SfiT 1WITNESSES: INVENTOR [m/id'zmmmfleceased,

3. 761a ATTORNEY Patented Dec. 25, 1951 .UNITED STATES PATENT OFFICEELECTROSTATIC DUST PRE CIPITATOR Ira R. Cummings, deceased, late ofCranford, N. J. by Margaret F. Cummings, executrix, Cranford, N. Jassignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., acorporation of Pennsylvania Application January 15, 1947, Serial No.722,131

7 Claims. 1

Broadly, this invention relates to electrostatic dust-precipitators of atype for removing foreign particulate matter of all sorts from a flowinggas; but, more-particularly, this invention is directed to providing aself-contained dust-precipitator of a small size which is suitable forcleaning air to be breathed in places like homes, small ofilces orstores, and in similar places or locations where the volume-rate of theair to be cleaned by the dust-precipitator is comparatively small and inthe order 'of several hundred cubic feet per minute.

i It isan object of this invention to provide a small electrostaticdust-precipitator of a type described which can be easily placed, withits parts readily accessible, in the air-circulating conduit of anair-conditioning system, which has automatic safety and protectivefeatures, and which requires little, if any, attention in order to keepit clean and efficient.

In the preferred form of this invention as herein described, electricalair-cleaning elements are utilized which can be operated with limitedenergy and do not generate objectionable or noxious gases. Preferably,the dust-precipitator is of the two zone or stage type comprising anupstream dust-charging or ionizer element and a downstreamdust-precipitating element in which precharged dust is precipitated orcollected. A form of such a dust-precipitator is shown in Patent No.2,129,783, granted. September 13, 1938,, to G. W. Penney, but otherforms are known.

It is among the specific objects of this invention to provide asmall-size dust-precipitator unit having built-in Washing means forcleaning at least'the dust-precipitating element. The washing means canbe manually operated, but an interlocking protective arrangement isprovided which automatically prevents operation of the washingmeanSwhile the dust-precipitating element is electrically energized. In aspecific arrang'ement, a valve is so provided inside the casing of: theunit that its operating means is interlocked with a part of the unit.This part may be a door or closure which controls the energization ofthe unit.

It is a more specific object of this invention to provide anelectrostatic dust-precipitator unit of-a'type describedwhich can beused alone or. can be installed in an air-conditioning system, such as ahotair heating system. To this end, provision is made in thedust-precipitator unit for optionally including a fan or blower forcreating a flow of air through the unit or to aid the air-movement inthe air-conditioning system.

Other objects, features and innovations of this invention will bediscernible from the following description of a preferred embodiment towhich, however, the invention is not limited. The description is to betaken in conjunction with the accompanying somewhat schematic drawingsin which details have been omitted for the sake of simplicity andclarity. In the drawings:

Figure 1 is an elevational view of a dust-precipitator unit embodying myinvention;

Fig. 2 is a similar view of the unit but with its front wall removed;

Fig. 3 is a vertical sectional view at right angles to the view of Fig.2;

Fig. 4 is a partial view of Fig. 3, showing the parts in a position forallowing access to the ionizer element and'the dust-precipitatingelement inside the unit;

Fig. 5 is a horizontal sectional view of a detail, taken on the line V-Vof Fig. 2, and illustrating how thewashing means is interlocked with adoor or closure of the unit;

Fig. 6 is a simplified wiring diagram for the equipment; and

Fig. 7 is a sectional detail view of a time-delay and switch means usedfor protection purposes.

The particular embodiment of the invention herein described comprises acasing, an air moving means in the form of a blower inside the casing, adust-precipitation means, a means for removing collected dust or dirtfrom the dustprecipitation means, and voltage-conversion and energycontrol means for controllably energizing the dust-precipitation means;the parts being specially arranged in the casing. The casing isindicated in its entirety by the reference numeral 2, and comprises asupporting base-frame 4, a top wall 6, a bottom wall 8, and upright sidewalls which are identified, for convenience, as a front wall II], a backwall l2, and opposite lateral side walls 14 and IS. A horizontalpartition 22, carried by bars secured to the side walls l4 and I6,divides the inside of the casing into an upper section or portion l 8and a lower section or portion 2D. The partition 22 terminates short ofthe front wall It in order to provide an intermediate opening '24 whichprovides open communication between the upper and lower sections 18 and20 of the casing.

The upper section is contains a voltage conversion and controlling meansand also an airmoving means. To this end, small inner dividing walls 28,3t and 32 are provided which cooperate with outer walls of the casing toform two small adjacent inner compartments 34 and 36 which are in anupper corner of the casing, and are closed in part by the front walliii. In this embodiment, the compartment 36 contains parts for thevoltage-conversion means and is longer than the compartment 86 whichcontains a valve for the washing means. The upper section it is alsoprovided with an airinlet opening 38 prefer ably located centrally inthe top wall 6 and defined by flanges to which a conduit may beattached, if desired. The inner compartments 3t and 3%; are at one sideof the inlet opening 38 and offer very little, if any, interference toincoming air flowing to the intake of a centrifugal blower ill. Thecentrifugal blower at is driven, through gearing, by an electric motor32; and these parts, constituting an air-moving means, are carried onthe partition 22. The tangential discharge end 45 of the blower fits theintermediate opening 2 through which the air is forced downwardly intothe lower section 2 of the dust-precipitator unit. a

The lower section 2b contains a dust-precipitation means 55 which iscarried'slightly above the bottom wall 8. It also contains a washingmeans 59 above the dust-precipitation means, and a slanted air-turningvane-structure 52 in front of the dust-precipitation means 46 and underthe intermediate opening 2 5.

The dust-precipitation means t5 can be any suitable structure such as,for example, that shown in Pegg Patent No. 2,380,992, dated August 'I,1945. Preferably, however, the dust-precipitating means at consists of.an assembly comprising a dust-charging or ionizer element or means 53,such as more particularly herein described and claimed in the copendingapplication Serial No. 722,133, filed concurrently herewith, which isnow Patent No. 2,447,933,. dated August 24, 1948, and adust-precipitating cell or means 56, such as more particularly hereindescribed and claimed in the abandoned application Serial No. 722,132,filed concurrently herewith. The precipitating cell 5!! comprises anouter framework having continuous rigid parallel opposite end platesbetween which a plurality of alternately relatively insulated anduninsulated plateelectrodes 58 and are parallely disposed. The frameworkhas wide-open. top and bottom sides, an open entrance end toward thevane-structure 52, and an open exit end close to an air-outlet opening32 in the lower portion of the back wall l2 of the casing. Preferablythe end plates are very close to the side walls is and E6 of the casing;and calking or baffles or some other means is used to bar air-flowbetween the end plates and the casing walls. The structureandarrangement is such that the dust-precipitation means iii extendsacross the side-to-side width of the casing but is not the fullfront-to-back depth of the casing. The height of the clust-'precipitation means 45 is less than that of the lower section so thatthe washing means 5!] can be disposed above it and below the partition22. a

The washing means 5% comprises an openbcttom box-lil ze structure formedin part by portions of the back wall 1?; and the partition 22. It alsoincludes apair of opposite walls 64 and (i5 which slope toward the endplates of the dustprecipitatin'g cell or element '55,, and an inner wallThe inner wall @313 extends straight downwardly from the back end of theintermediate opening 2 5 and completely across the casing so as to form,with'the front wall ill, a downwardly extending gas-passage To forguiding air an be.

. from the blower 40.

- cludes a plurality of nozzles 18 located at different pointsdistributed over the dust-precipitation means 46 and adapted to throwout sprays of water for washing dirt out of the dust-precipitationmeans. The spent water containing the dirt flows to the bottom wall 8which slopes to a drain 8c. Spray water is prevented from splashing outof the casing, through the outlet opening 62, by a water deflectingmeans 82 comprising a plurality of suitably shaped and placed louvers 8%which have portions sloping downwardly toward the front of the casing.Preferably the outlet opening'62 is about the same size as the exit endof the dust-precipitation means 46.

The dust-precipitator is arranged so that it will clean the air whilethe air is flowing horizontally, although the air flows vertically intoit. The air flowingdownwardly at the end of the vertically extendinggas-passage 78 is turned by the vanestructure 52 horizontally into theentrance end of the dust-precipitation means 46, ,more specifically,into the dust charging element 54. Consequently, the vane-structure 52can be considered as being at the intersection of the vertical linesofair flow through gas-flow passage 10 and the horizontal air-flow linesthrough the dust-precipitation means 46. It is also desirable to causeall of the air flowing through the unit, and especially the air whichhas passed through the dust-charging element 54, to pass through thedust-precipitating element 56. Accordingly,

' the inner wall 68 meets the vane-structure 52 resented by the dot-dashrectangle, such voltage-- conversion means is mounted in the compartment3% and comprises various parts including capacitors, resistors, atransformer meansrand rectifiers properly connected to constitute apower pack 88 for converting a commercialA. C. supply available at acord or conductors 90 extending into the casing, to the required;,highvoltage D. C. supplied to insulated conductors $2 and Q4 and a groundconnection 96. The insulated conductors 92 and 94 are suitably securedinside the casing and extend to therespective insulated electrode groupsof the-dust-precipitation means 46.

The washing means 50 must be connected .to a supply of washing fluid.The usual; tap water supply system-is recommended for general purposes.The network p-ipinglG of the washing means includes a connection 98 atan outer wall' of the casing to which a Watersupply pipe can tends fromthe valve Hill to the network 16 which includes the nozzles 78. beprovided in this feed pipe or in the supply'pipe outside the casing. Thecontrol valve I00 is preferably of the on-ofi type and has amanually Athrottle valve may operable member in the form of a handle I04 for iscut off. To this end, the front wall I0 of the casing 2 comprises aplurality of interlocked movable members which serve as doors orclosures for the casing. In this particular embodiment, the front wallIn comprises a large removable closure member I06 that water-tightlycovers almost the entire front side of the casing except for thecompartment 36. The last is covered by a separate small door I08 hingedto the closure member I06 and separately fastenable to the casing.

In order to open or close the door I08, it is necessary to manually turna screw 0' which passes through a hole in the door, and fits a nut H2,or the equivalent, fixed to a bracket structure II4 secured inside thecasing, preferably to the dividing walls forming the compartment 36. Thenut is near the front opening which is closed by the door I08; and thedistance between it and the door in closed position, is considerablyless than the length of the screw IIO so that several turns are requiredto fully thread the screw through the nut. At the end of its movement,the screw engages and closes a switch II6 which may be of theconventional push button type. The switch is in the low voltage supplyof the voltage-conversion means, as for example, in se ries in thecircuit of the conductors 90. When it is desired to open the door I08,itis necessary to thread the screw IIO out of the nut II2. The firstmovement of the screw opens the switch I I6, thereby deenergizing thepower pack 88 and removing high voltage from the dust-precipitationmeans 46. However, before the door can be opened, several moments areconsumed for fully removing the screw from the nut after the switch.

IIG has been opened. During this time any charge on the capacitors ofthe power pack will dissipate. A similar protective time-delay switchmechanism comprising a screw I I0 and a switch I I6 is provided for theclosure member I06.

As shown in Fig. 6, the energizing conductors 90 feed the power pack 88and the blower motor 42 in parallel. The supply of power is controlledby switch IIS and H6 both of which must be closed in order to makeoperating power available in the dust-precipitator unit. Additionalmanually operable switches I20 and I22 are separately provided forindependently controlling the power pack and blower, respectively. If itis desired to operate the blower without operating the power pack, theswitch I20 can be placed in open position. If the dust-precipitator unitis utilized in systems having their own draft-inducing means, the blower40 and its motor 42 can be entirely omitted from the unit.

For washing the dust-precipitation means, only the door I08 need beopened for access to the compartment 35 where the handle I04 of thecontrol valve I00 is located. However, the valve and handle are sodisposed that the handle lies within the compartment only when the valveis closed. The handle can be turned to open the valve only when the doorI08 is opened, because in valveopening position the handle projectsoutward through the opening normally closed by the door. Consequently,the door can be closed only when the water supply is shut off, and thewashing means 50 is operable only while the door is open. Since openingof the door I08 also opens the switch H6, it is evident that the washingmeans is operable only while the high voltage parts ot thedust-precipitator unit are deenergized.

It is also desirable to provide access to the interior of thedust-precipitator unit, especially the dust-precipitation means 48. Tothis end, the vane-structure 52 is removably fastened in the casing andcan be removed through the front wall opening which is exposed when theclosure member I06 is opened. The water-defleeting means 82 may also beremovably secured to the casing. In order to provide ready access tothe; dust-charging means 54 without disturbing the dust-precipitatingmeans 56, the high voltage parts of the former are built as a hingedunit which can be moved forwardly so as to protrude out of the frontopening of the casing as indicated in Fig. 4. The baffle 86 acts as astop for holdin the dust-charging means in tilted position. In suchposition it is easy to repair or replace an ionizing wire or to reachinside the dust-precipitating means 56 for any purpose.

While the invention has been described in a preferred form, it isobvious that other forms and embodiments can be built embodying theteachings of this invention; and as time goes on it may be expected thatmany changes will be made in the embodiment herein described so thatforms of my invention may eventually be radically difcomprising aplurality of upstanding spaced precipitating-electrodes providing aplurality of gaspassages therebetween from which gas flows toward saidoutlet opening, said dust-charging means and said dust-precipitatingmeans being generally horizontally displaced, an inner wall inside thecasing spaced from the other of said side walls for providing adownwardly directed gas-passage thereat for receiving gas from saidinletopening, and an air-deflecting vane-struc-' ture at the bottom of saidgas-passage for turninggas from said gas-passage horizontally to wardssaid dust-charging means.

2. A self-contained electrostatic dust-precipitator unit comprising acasing including upstanding side walls, said casing having an inletopening in the top thereof and an outlet opening, an electrostaticdust-precipitation means inside the casin and comprising an upstreamdustcharging means and a downstream dust-precipitating means, the lastcomprising a plurality of upstanding spaced precipitating-electrodesproviding a plurality of gas-passages therebetween, said dust-chargingmeans and said dust-precipitating means being generally horizontallydisplaced, said casing including an inner wall spaced from said casingside walls and providing a side of a downwardly directed gaspassageinside the casing, means for horizontally turning gas from saidgas-passage for flow through said dust-charging means and said pluralityof gas-passages, and liquid discharging means on a level with said innerwall for washing said 'pr'ecipitating-electrodes.

'3. A self-contained electrostatic dust-precipitator unit comprising acasing having a top wall with an opening therein, partition means insaid casing providing an upper portion and a lower portion therein, saidpartition means providing an inner opening between said upper and lowerportions, an electricaldust-precipitation means under said partitionmeans, said electrical dustprecipitation means having horizontallydisplaced gas-entranceand gas-exit ends, washing means under saidpartition means and above said dust-precipitation means for washing thelast, said washing means comprising wall-means for diverting gas flowtherefrom and directing gas from said inner opening to said gas-entranceend of the dust-precipitation means.

4. A self-contained electrostatic dust-precipitator unit comprising acasing having a bottom Wall sloped to a drain, partition means in saidcasing providin an upperportion and a lower portion therein, said casinghaving an inlet opening at said upper portion and an outlet opening atsaid lowerportion, said partition means providing-an inner openingbetween said upper and lower' portions, an electrical dust-precipitationmeans under said partition means and above said bottom wall, saidelectrical dust-precipitation means having open top and bottom sides andhorizontally displaced gas-entrance and gasexitends, means providing agas-passage for directing the gas passing through said inner opening tothe gas-entrance. end of the dustprecipitation means, washing meansunder said partition means and above said dust-precipitation means forwashing the last, said washing means being on a level with a part ofsaid gaspassage.

5. A self-contained electrostatic dust-precipitator comprising a casinghaving a front wall, a bottom walland opposed side walls, partitionmeans in said casing providing an upper portion and a lower portiontherein, said casing having an inlet opening at said upper portion andan outlet opening at said lower portion, said partition'means providingan inner opening between said upper and lower portions, an electricaldustprecipitation means under said partition means, said electricaldust-precipitation means having horizontally displaced gas-entrance andgas-exit ends, said gas-exit end being at said outlet opening, meansproviding a gas-passage for directing gas from said upper portion ofsaid casing to the gas-entrance end of the dust-precipitation means, acentrifugal blower in said'upper portion of said casing, said blowerhaving a tangential discharge discharging directly into said gas-passagemeans, and washing means under said partition means and above saiddust-'precipitation means for washing the last, said washing means beingon a level with a Part of said gas-passage, said washing meanscomprising wall-means for diverting gas flow therefrom.

6. A self-contained electrostatic dust-precipitator unit comprising anenclosing casing having an outer top wall, an outer bottom wall, anouter front wall, an outer back wall and outer side walls, said front,back'and side walls being upright, said casing having an air-entranceopening and an air-exit opening in the bottom part of one of saidupright walls, an electrical dustprecipitation means inside said casinghaving a pair of open upright sides for horizontally flowing air toenter and leave, said dust-precipitation means having top and bottomopensides,

means providing a gas-passage in said casing between said air-entranceopening and one of said pair of open sides, the other of said pair ofopen sides being substantially at said air-exit opening, saidgas-passage providing means comprising an inner wall having a lower edgedefining a part of the upper boundary'of said gaspassage, washing meanscomprising a plurality of nozzles above and distributed over said topopen side of said dust precipitating means, said nozzles being higherthan said lower edge.

'7. A self-contained electrostatic unit as defined in claim 6 butfurther characterized by said bottom wall being sloped to a drain and bya liquid-diverting means comprising a plurality of louvers in saidair-exit opening.

' MARGARET F. CUMMINGS,

Executr ia: of the Estate of Ira, R. Cummings, De-

ceased.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

